Question

Consider the following statements regarding $ABO$ blood group in human.
I. It is controlled by multiple alleles.
II. It shows codominance.
III. Codominance can be manifested phenotypically in human.
IV. It follows the Mendel's law of inheritance.
Which of the statments(s) given above are correct?

• A. Only I
• B. I and II
• C. II and III
• D. IV and II

Answer 1

Answer: (B)

Statements I and II are correct. Statements III and IV are incorrect and can be corrected as
• Codominance cannot be manifested phenotypically in humans as $ABO$ blood group in humans is three alleles of gene $I\left(I^A,I^B,i\right)$.
• $ABO$ blood grouping system in humans does not follow Mendel's laws of inheritance.